Answer:
0.70046 m/s²
2.732862 N
Step-by-step explanation:
g = Acceleration due to gravity = 9.81 m/s²
m = Mass of yo-yo = 0.3 kg
R = Radius of rolling disk = 5.1 cm
r = Radius of rod = 1 cm
For a rolling disks the acceleration is given by

The acceleration of the yo-yo is 0.70046 m/s²
The tension in the string will be

The tension in the string is 2.732862 N